How to get data?

Hi!
How can I get layer with power lines or just coordinates of power poles from http://chernigivoblenergo.com.ua:8889?

That website appears to be displaying data over the top of normal OSM tiles. You’d need to ask whoever operates that website where they get their data from.

Also you need to define what you mean by “layer” - layer in what? Some sort of GIS system? A slippy map JS framework such as Leaflet? Something else?